PIP query

This really is for a friend. He gets PIP higher mobility standard care. I think he will lose all of his PIP as he has previously embroidered his disability. His only other income is ESA support group. He says he has no savings and just a very small private pension. He hasn't been asked to migrate to UC yet. He also has current legal troubles and will have to borrow money to pay his legal fees. My question is if/when he loses his PIP what will he do for income? He is too ill to work but I don't think he fits the descriptors. Would he then have to claim UC. He He is aged 64. He gets help with the council tax. Also he wasn't due a review until next year so it seems to have arrived early. TIA